According to the American Heart Association, over 60% of men and nearly 50% of women are overweight. Furthermore, approximately 13% and 18% of men and women, relatively, are obese. Being sedentary and overweight can lead to metabolic syndrome, which is characterized by a group of metabolic risk factors in one person. They include: (a) central obesity, indicated by excessive fat tissue in and around the abdomen; (b) atherogenic dyslipidemia (blood fat disorders, mainly high triglycerides and low HDL cholesterol, that foster plaque buildups in artery walls); (c) elevated blood pressure (130/85 mmHg or higher); (d) insulin resistance or glucose intolerance (the body can't properly use insulin or blood sugar); (e) prothrombotic state (e.g., high fibrinogen or plasminogen activator inhibitor [−1] in the blood); and (f) pro-inflammatory state (e.g., elevated high-sensitivity C-reactive protein in the blood).
The underlying causes of this syndrome are overweight/obesity, physical inactivity and genetic factors. People with metabolic syndrome are at increased risk of coronary heart disease, other diseases related to plaque buildup in artery walls (e.g., stroke and peripheral vascular disease) and Type 2 diabetes. According to the American Diabetes Association, 20.6% of adults over the age of 60 have diabetes and 34.8% of all adults have either diabetes or pre-diabetes. Metabolic syndrome has become increasingly common in the United States. It is estimated that about 20-25 percent of US adults are affected. The syndrome is closely associated with a generalized metabolic disorder called insulin resistance, in which the body cannot use insulin efficiently. Metabolic syndrome is also called insulin resistance syndrome, which leads to Type 2 diabetes.
There have been many studies reporting the health benefits provided by bioflavonoids isolated from various plants. The potential role of bioflavonoids in the prevention of cancers and cardiovascular disease and the treatment of inflammatory diseases has been documented. Thousands of naturally occurring bioflavonoids derived from various plants have been classified according to their chemical structure. These classes are flavones, isoflavones, flavan-3-ols and anthocyanidins. Flavones are divided into four groups: (1) flavones, which include, e.g., luteolin, apigenin and tangeritin; (2) flavonols, which include, e.g., quercetin, kaempferol, myricetin, chrysin, rutin, rhoifolin, morin, fisetin, isorhamnetin, pachypodol and rhamnazin; (3) flavanones, which include, e.g., galangin, hesperetin, naringenin, naringin, neohesperidin, hesperidin, narirutin, pruning, eriodictyol, homoeriodictyol; and (4) 3-hydroxyflavanones or 2,3-dihydroflavonols, which include, e.g., dihydroquercetin and dihydrokaempferol. Examples of isoflavones include, e.g., genistein, daidzein and glycitein. Flavan-3-ols include, e.g., catechins, gallocatechin, catechin 3-gallate, gallocatechin 3-gallate, epicatechins, epigallocatechin, epicatechin 3-gallate and epigallocatechin 3-gallate. Anthocyanidins include, e.g., cyanidin, delphinidin, malvidin, perlargonidin, peionidin and petunidin.
Flavonoid availability and activity varies greatly among the natural sources of flavonoids. In order to obtain the healthful benefits of many flavonoids, large doses are required, which is often impractical and too costly.